Forced air heating and air conditioning systems commonly include an air filter to remove particulates and other impurities from the circulating air. These air filters generally consist of a filter media (e.g., a fibrous mat or porous foam) that is held within a frame. The frame provides the air filter with mechanical strength and rigidity so as to facilitate mounting of the air filter in the air handling equipment. Frequently, these air filters must be replaced on a periodic basis. Alternatively, the air filters can be designed to be washable.
Unfortunately, the air filters that are commercially available for use in heating and air conditioning systems have a number of shortcomings. For example, the air filters are relatively expensive to transport and store because they are quite bulky despite their lightweight construction. This problem has been alleviated somewhat by filters having frames that are designed to nest in another filter thereby allowing more filters to be stored in a given shipping container. However, even with nestable filter designs, the transport and storage of the filters remains a significant cost issue. Moreover, nestable filter designs, as is the case with many conventional filter designs, tend to be expensive to manufacture, awkward to assemble and somewhat flimsy.